Odoo V10 Enterprise self-hosted

We need to put the Unit of Measure of the products page so customers what qty they are buying. We have some that come in various amounts. It is all set up, however we want to display it on the page for customers to see. I've added in this line:

<span t-field="product.uom_id.name" style="white-space: nowrap;"/>

And the UoM appears if you are logged in. If someone is not logged in, when they view the product page, they get "500: Internal Server Error". I've found online it is apparently a permissions issue, but not sure what permission I need to add or change to resolve this issue. Is there another way to show and enable UoM on the product page, or how can I resolve this?